codevise/pageflow — pull request #231 by tf (2014-12-19 17:27:30+00:00)
Title: Introduce PositionedFile Decorator

Let `Page#thumbnail_file` and `Entry#thumbnail_file` return
`PositionedFile` objects which provide a `thumbnail_url` and also
background positioning information. The positions are either read from
the sharing image or the corresponding file positions of the page
thumbnail candidate.